It happens once a year, in the summer. If you don't look closely enough, you may miss it altogether. If it's raining, it may not occur at all. But if you know where to search the skies and the weather is clear, all you have to do is look. The star lovers willmeet in the sky once more.

Try it. Gaze up at the evening sky at the right time of the year, amid the stars of the River of Heaven -- the Milky Way to you and me -- and if you're lucky, you'll see the Weaver Princess and the Cowherder meeting in the skies after spending an entire year apart, reunited on the wings of the star ravens.

Of course, that only occurs if the weather is clear. If it's not -- if rain or fog prevents them from finding each other -- the star lovers must wait another year. The torrential rains that summer sometimes brings are the star lovers, weeping in frustration.

Astronomers call them Vega and Altair, but those designations are so cold. When the Weaver Princess and the Cowherder finally meet in the sky, mortals on Earth celebrate the "romance of the Milky Way," as the ancient poems refer to the Tanabata, or the Festival of Stars.

The legend goes like this. The Emperor of the Sky ruled from his palace wrought of silver and gold and jewels of fire on the banks of the Milky Way, while his daughter, the Weaver Princess, had the task of picking the stars and designing the rich and bejeweled cloth for the gods of the constellations.

One day, she met the Cowherder as he tended his herd on the banks of the River of Heaven. They fell in love, and in their rapture, they neglected their duties. The stars went unpicked, the cloth went unwoven, and the celestial herd went untended.

When the Emperor learned that the Princess and the Cowherder were neglecting their duties, he became angry and, in his fury, sundered the River of Heaven, ripping the star lovers apart. Upon hearing their pleas, he relented, decreeing that if they tended to their tasks, they could meet once a year.

Toward this end, the Princess and the Cowherder are allowed to have help in the form of their servants the ravens, who spread their wings to bridge the River of Heaven so that the star lovers can meet in the middle. On that day, it is the duty of the ravens to help the star lovers come together. Sometimes inclement weather prevents them from meeting atop the wings of the ravens; the rain and the wind rise and overwhelm them, blinding them and driving each away from the other. If that is the case, they must wait another year.

Sometimes, however, when the stars shift in the sky, the star lovers are a little farther apart than they should have been, and they struggle to reach each other. And reach each other theymust; unless they do so, eventually, the stars will shift away from each other, never to meet again.

If that were to happen, the star lovers will diminish, their lights fading from the luminance of the sky forever.